Sandpaper cot



Dec. 7, 1965 J. H. LEWIS ETAL SANDPAPER COT Filed Aug. 9, 1963 FIG INVENTORS John A. Lew/s BY John H Lewis ATTORNEY 3,221,449 SANDIAPER COT John H. Lewis, Archdale, and John A. Lewis, Trinity,

N.C., assiguors to Archdaic Belt Company, Inc, Archdale, N.C., a corporation of North Carolina Filed Aug. 9, 1963, Ser. No. 391,085 3 Claims. ((11. 51-373) This invention relates to deformable revolving pneumatic drums supporting abrasive bands for finishing materials, and relates more particularly to an inflatable revolvable cylinder for supporting an abrasive band or sleeve protectively insulated from the supporting drum cylinder by an intermediate protective covering which abrasive band is utilized for abrading or flushing wood, metal or plastic, among other materials.

In the manfuacturing processes for finishing those articles whether of wood, metal or plastic, suitable abrasives bonded to cloth or paper strips or sheets are utilized. extensively for the application of final or intermediate finishing operations. In the application of the finishing operations of some articles, a deformable membrane, such as a pneumatically inflatable bladder is desirable in order to achieve the desired finished contours to the article being finished. One such application is the utilization of a cylindrical drum formed. with spaced apart flanges mounted on a longitudinally extending tube with the cylindrical surface of the drum being formed by an inflatable tube of rubber or other suitable material sufliciently flexible and durable to stand repeated flexures and distortion while maintaining the desired outer inflated configuration. The inflatable bladder is retained on the flanges by a suitable means. A commercially available inflatable drum is manufactured by Ekstrom Carlson and Co.

Heretofore, the deformable diaphragm or membrane forming the cylindrical surface of the drum has been protected by means of a canvas cot or covering provided at the terminal ends with a wire or other clamping member to retain the woven canvas cover around the ends of the drum flanges. The woven canvas cot protective covering is provided with an overlapping seam to form the bladder protective covering. After relatively short periods of operation, a sandpaper band. or other abrasive covering mounted over the seamed canvas cot will become frayed or torn rendering the sandpaper band unsuitable for further use. Frequently the canvas cot will become worn rapidly even though care is exercised in replacement of the abrasive bands. Diaphragm or membrane replacement may also be necessary in the event the canvas cot requires replacement due to wear exposing the deformable cylindrical surface to Wear that will result in damage and utimately require replacement.

The high cost of sandpaper band or sleeve replace ment as well as replacement of the worn canvas protective cots becomes prohibitive in large scale operations. In addition to replacement of expendable sandpaper bands, careless operators will not replace worn canvas protective cots when necessary thereby exposing to damage the costly inflatable bladder which may be cut, punctured or worn thereby necessitating repairs or replacement.

It is, therefore, an objective of this invention to provide a protective cot for the deformable drum that may be readily mounted over the drum and will reduce wear to the abrasive covering and prolong the life of the deformable bladder member.

Another objective of this invention is to provide a knitted seamless protective cot that is sufliciently deformable and stretchable to be supported over an inflatable bladder member for receiving thereover an enveloping abrasive surfaced band or sleeve.

A United States Patent Still a further object of this invention is the provision of a durable circular knit seamless sleeve having a single or multiple thickness and. knit from synthetic yarns that may be stretchable so as to impart maximum wear resistance and flexibility to the cot to prolong the life of the encompassing abrasive band or sleeve.

Still another objective of this invention is to provide a seamless circular knit protective sleeve member for enveloping a deformable pneumatic drum or other desired configuration so as to provide a protective lining for the drum and over which lining a suitable abrasive belt or sandpaper band may be supported for revolving at suitable speeds of revolution.

Other objects and many of the attendant advantages of this invention will become more readily apparent to those skilled in the art of grinding and finishing operations from the following detailed description taken in conjunction with the accompanying drawing, and wherein:

FIG. 1 is a front elevational view, with sections removed, illustrating one embodiment of the present invention in combination with a deformable pneumatically inflatable cylindrical drum;

FIG. 2 is a somewhat enlarged. transverse sectional view taken substantially along the plane of section line 2-2 of FIG. 1;

FIG. 3 is a greatly enlarged presentation of a portion of a knitted fabric embodying one knitted fabric construction for the seamless protective cot;

FIG. 4 is a greatly enlarged section of a circular knit fabric embodying a second alternative knitted construction; and

FIG. 5 is a greatly enlarged portion of a circular knit seamless fabric embodying another knitted fabric construction for the protective cot.

Referring to the drawing and particularly to FIGS. 1 and. 2 there is illustrated one embodiment of the present invention shown in combination with a pneumatic or air inflatable cylindrical drum 10 of the type manufactured and sold by Ekstrom Carlson and Co. wherein the laterally spaced apart deformable membrane-receiving flanges 11 and 12 are securely mounted on a longitudinally extending tubular shaft 13. A deformable and inflatable tubular diaphragm or membrane 14 which may be made of rubber or other suitable material that is deformable readily without tearing or breaking is supported at the terminal ends 15 and 16 within an annular recess 17 provided in each of the flanges 11 and 12. Suitable clamping means is provided for securely anchoring the terminal ends of the membrane in the flanges to withstand internal as well as external pressure and forces applied to the cylindrical surface of the tubular deformable member.

The pneumatic drum or pump as it is sometimes referred to in the trade has a leakproof seal at all of the joints so that air under pressure may be introduced into the chamber formed between the interior of the membrane 14 and the exterior of the shaft 13 through the valve 18 threadably secured in the head. of flange 11. Adequate pressure and volume of air is introduced. through valve 18 to inflate the deformable membrane 14 to its desired contour which in the embodiment illustrated forms a cylindrical surface for receiving a sandpaper or other abrasive material that is surfaced on the sleeve or band 19. Depending upon the physical characteristics of the abrasive materials employed, a paper or cloth backing may be utilized. After prolonged use of the band or sleeve 19, the band may wear or be cut by the surface of the material being finished and the tubular member of diaphragm 14 may be punctured or torn necessitating replacement. A circular knit seamless protective cot or sleeve 20 is interposed between the band or finishing sleeve 19 and the tubular member 14 so as to provide a smooth continuous surface without any ripples or wrinkles therein that will mar the surface of the material being finished or provide any rough portions for the band 19.

Utilizing a circular knit sleeve of either plain or rib knit fabric that is sufficiently stretchable over the entire cylindrical length of the pneumatic pump 10 is desirable so as to protect the finishing band 19 from engaging the edges of the flanges 1i and 12 as well as any portion of the membrane 14. The protective cot 20 illustrated in FIGS. 1 and 2 has a double thickness of fabric or two plies, 20A representing the outer layer, and 20B representing the inner layer of the continuous sleeve 20. The ends 21 and 22 of the protective cot or sleeve 20 overlap the terminal ends of the flanges 11 and 12 and there is normally sufiicient friction to maintain the protective cot in place over the flanges. However, in some instances, a wire band 25 may be interlaced through the knitted fabric or a suitable hem may be provided which the wire band 25 may be laced and fastened to secure the protective cot 20 in place.

In one preferred embodiment of the protective cot 20, a circular knitting machine is employed for knitting continuously courses of knitted fabric made from two plied ends of 70 to 100 denier rnultifilament stretchable nylon yarn thereby providing an extremely durable and stretchable protective cot for mounting directly over the pneumatic drum 10. As shown in FIG. 3, each of the courses 22, 23 and 24 of the plain knit fabric is knit from nylon yarns of multifilament construction in which the yarns have previously been processed to impart a crimp through conventional false-twist and heating operations, or other known procedures for imparting stretchable characteristics to the nylon yarn. It will be readily apparent that while a plain knit fabric is shown in FIG. 3, this invention may utilize the protective cot 20 being knit from rib knit fabric made of stretchable nylon yarns as well. The primary objective is to eliminate any seams or projections in the cot which will cause a non-uniform surface to appear facing the sandpaper or other type band 19.

An alternative knitted construction is shown in FIG. 4 wherein the fabric 27 differs from the fabric 28 shown in FIG. 3 in that alternate courses 29 of the circular knit fabric are knit from an inelastic yarn, such as rayon or nylon to which no crimp or stretch processing application has been made and the intermediate courses 30, only one of which is shown, will be knit from stretchable nylon multifilament yarn of the desired denier. Suflicient stretchability and strength characteristics will be achieved utilizing the fabric 27 whether of plain or rib knit construction. However, it is preferable that the non-stretchable yarns making up the alternate courses and the stretchable yarns making up the intermediate courses will be substantially of the same overall diameter so as to present a uniform surface and will avoid ridges throughout the cylindrical extent of the cot.

A further modification is illustrated in the fabric 31 as shown in. FIG. wherein all of the courses of the circular knit fabric, 32, 33 and 34, may be knit of an inelastic yarn of suitable denier or count with an elastic yarn 35, whether of rubber or spandex, covered or uncovered, will be laid-in without knitting in selected courses throughout the sleeve or cot.

It Will be readily apparent that the sleeve 20 will be continuously knit on a circular knitting machine to any desired length or an indeterminate length, as desired, and the requisite length may be achieved subsequently by cutting and finishing by providing a suitable seam in the cut fabric to prevent ravelling. A double-ply or double-thickness sleeve may be provided simply by sewing together two separate lengths for covering a drum of a particular length or a sleeve length may be provided. that is twice or longer than twice the overall length of the drum and inverting a portion so as to form the inner layer and binding the terminal ends together either to form a seam for preventing ravelling or a hem for receiving a wire or other securing member to retain the cot on a drum.

In the preferred form of protective cot, the circular knit sleeve knit with two ends of stretchable multifilament nylon yarn having a total of denier or greater will last at least twice as long as a woven cotten canvas cot that has been seamed longitudinally. Furthermore, the increased wear life of the bands for finishing the materials have also been increased.

It will be readily apparent that many modifications may be made to the knitted fabric construction for the protective cot for use in combination with the penumatic or air inflatable drum without departing from the purpose and use of such seamless knit fabric in combination with such drum, and such modifications are contemplated within the scope of the appended claims.

What is claimed is:

1. In combination with an inflatable deformable drum for receiving an encircling abrasive-covered sleeve, said drum having spaced apart end flanges, a tubular flange supporting shaft and an inflatable tubular bladder supported on said flanges to receive and retain an air inflatable deformable cylindrical surface, a seamless knit sleeve covering said inflatable bladder and at least part of said flanges, and an abrasive-covered sleeve encircling said knit sleeve for at least a length to cover said bladder.

2. In combination with an inflatable drum for receiving an encircling abrasive-covered sleeve, said drum having spaced apart flanges, a flange supporting shaft and a deformable inflatable tubular bladder forming a cylindrical surface, a seamless knit sleeve covering said inflatable bladder, and an abrasive-covered flexible sleeve encircling said knit sleeve for at least a cylindrical length to cover said bladder.

3. In combination with a deformable air-inflatable drum for receiving an encircling abrasive-covered member, said drum having spaced apart end flanges, a supporting shaft and an inflatable bladder supported on said flanges, a seamless knit stretchable sleeve covering said inflatable bladder, and an abrasive-covered member encircling said knit sleeve covering said bladder.

References Cited by the Examiner UNITED STATES PATENTS 1,045,201 11/1912 Shoop 51-373 2,225,073 12/1940 Miller 51-373 2,365,268 12/1944 Herter 66-170 2,804,762 9/1957 Kameda 66-170 ROBERT C. RIORDON, Primary Examiner. LESTER M. SWINGLE, Examiner. 

3. IN COMBINATION WITH A DEFORMABL AIR-INFLATABLE DRUM FOR RECEIVING AN ENCIRCLING ABRASIVE-COVERED MEMBER, SAID DRUM HAVING SPACED APART END FLANGES, A SUPPORTING SHAFT AND AN INFLATABLE BLADDER SUPPORTED ON SAID FLANGES, A SEAMLESS KNIT STRETCHABLE SLEEVE COVERING SAID INFLATABLE BLADDER, AND AN ABRASIVE-COVERED MEMBER ENCIRCLING SAID KNIT SLEEVE COVERING SAID BLADDER. 